1. Field of the Invention
This invention relates to windshield wiper arms and blades and, more particularly, to an adaptor for connecting a U-shaped wiper arm to a pin-type connector on a wiper blade.
2. Description of the Prior Art
Adaptors for converting one type end of a windshield wiper arm to another type end have been broadly known for some time. Typical of the known type adaptors would be that shown in U.S. Pat. No. 3,588,942 to F. J. Schlesinger and U.S. Pat. No. 3,874,019 to P. J. Speth wherein adaptors are provided for converting a straight end wiper arm to a pin-type wiper arm whereby the straight end arm can be connected to a pin-type connector on a blade. The adaptors of the above-mentioned U.S. Pat. Nos. 3,588,942 and 3,874,019 could not be used with a hook end arm to connect the hook end arm to a pin-type connector on a blade.
Another example of an adaptor is shown in U.S. Pat. No. 3,843,994 to P. G. K. Smithers wherein an adaptor is provided for converting a hook end arm to a pin-type arm whereby the hook end arm can be connected to a pin-type connector on a blade. The adaptor includes a horizontally U-shaped sheet metal member with the legs of the "U" lying parallel to each other and being spaced apart substantially the same distance as the width of the hook end arm. A pair of detents extend inward from each leg of the "U" of the adaptor. A cylindrical spacer supports the legs apart near the base of the "U" and a pin passes transversely to the plane of the legs of the "U" and through the spacer. The hook end arm extends around the spacer and pin and between the legs of the "U" with the detents retaining the arm against rotation relative to the pin. In practice, it has been found that the legs of the "U" of the adaptor spread, releasing the arm, thereby permitting rotation of the arm relative to the adaptor so that control of the blade is lost.
U.S. Pat. No. 3,896,519 to H. G. Pankow and U.S. Pat. No. 4,057,869 to R. A. Longman et al, both show connectors directly on blades that are adapted to connect a hook end arm (U.S. Pat. No. 3,896,519) to a blade or to connect both a hook end arm and a straight end arm (U.S. Pat. No. 4,057,869) to a blade. Both the U.S. Pat. Nos. 3,896,519 and 4,057,869 patents show different specific structures for connecting a particular arm end to a blade. In both cases, the designs of the connectors leave something to be desired in practicality, i.e. the spring can become lost in the U.S. Pat. No. 3,896,519 structure and the onepiece plastic configuration of the U.S. Pat. No. 4,057,869 structure is subject to failure and cannot be used with a side pin-type connector on a blade.